Hey 16V engine experts!!

How hard is it to replace the timing chain tensioner on a 16V? My timing chain rattles when starting cold and needs to be replaced. I'd like to also replace the tensioner with the updated version, that holds the chain until oil pressure builds up. So, does the entire engine have to be removed to replace the tensioner, or does just the head have to be removed. I'm having the guides replaced and valves ground this winter anyway, so could the tensioner easily be replaced at the same time?

Thanks in advance!!

Daniel
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87 190E-16V Blk/Blk 5Spd